Emanuel Pogatetz issued a public apology last night for the reckless studs-up tackle that left Manchester United's teenage Brazilian midfielder Rodrigo Possebon in hospital, and accepted that he had deserved to be sent off in Tuesday's Carling Cup third-round tie at Old Trafford.

Possebon was kept in hospital overnight and needed stitches to a two-inch gash below his right knee, but the 19-year-old will reflect that he had a lucky escape after x-rays showed there was no break.

Sir Alex Ferguson, who had admitted he feared a long-term injury, accused Pogatetz of a "horrendous" and "terrible" challenge and there was further condemnation yesterday, with the former United and Middlesbrough defender Gary Pallister accusing the player of knowing he was going to hurt his opponent.

Pogatetz, however, insisted it had not been premeditated. "Firstly, I have to say that I went for the tackle because I thought I could win the ball. I now accept, however, that I misjudged the challenge," said the Middlesbrough captain. "Immediately after the incident, I did not think it was a red-card offence because I did win the ball. But now I have had the chance to see the tackle on television, I know the referee was right to send me off."

Pogatetz said he had sent a message to Possebon and would try to contact him in person. His contrition will not spare him from a club fine and a three-match ban, while the incident will do little to improve the reputation of a defender who refers to himself as "Mad Dog" and, as a Spartak Moscow player in 2005, was banned for 24 weeks, reduced to eight on appeal, after breaking an opponent's leg.

The Football Association is currently unable to increase Pogatetz's ban without issuing a separate charge but his case is likely to strengthen its will to introduce a sliding scale for the length of suspensions after the receipt of a red card from next season. The FA plan was revealed after the Newcastle midfielder Danny Guthrie's suspension for kicking the Hull forward Craig Fagan remained at three games despite calls for a longer ban.

"You can mistime a tackle now and again but he was sliding over the ball," said Ryan Giggs, United's captain during a 3-1 victory for Ferguson's team. "That was a bad challenge and the referee has rightly sent him off."

Pallister was even more critical. "Everyone knew immediately it was a bad one," he said. "Pogatetz tried to give it the innocent look but when you see it in slow motion he's actually hit the ball first but the angle he is tackling he knows he is going to hit Possebon's leg. And he does - with great force. Pogatetz has got that part to his game sometimes. He likes to steam in but this was a bad one and he is going to have to face the consequences."